class_docstr: Pie graph class
docstr: Make a serie slice
docstr_tok: ["Make","a","serie","slice"]
code: def slice(self, serie, start_angle, total):
      """Make a serie slice"""
      serie_node = self.svg.serie(serie)
      dual = self._len > 1 and not self._order == 1
  
      slices = self.svg.node(serie_node["plot"], class_="slices")
      serie_angle = 0
      original_start_angle = start_angle
      if self.half_pie:
          center = (
              (self.width - self.margin_box.x) / 2.0,
              (self.height - self.margin_box.y) / 1.25,
          )
      else:
          center = (
              (self.width - self.margin_box.x) / 2.0,
              (self.height - self.margin_box.y) / 2.0,
          )
  
      radius = min(center)
      for i, val in enumerate(serie.values):
          perc = val / total
          if self.half_pie:
              angle = 2 * pi * perc / 2
          else:
              angle = 2 * pi * perc
          serie_angle += angle
          val = self._format(serie, i)
          metadata = serie.metadata.get(i)
          slice_ = decorate(
              self.svg, self.svg.node(slices, class_="slice"), metadata
          )
          if dual:
              small_radius = radius * 0.9
              big_radius = radius
          else:
              big_radius = radius * 0.9
              small_radius = radius * serie.inner_radius
  
          alter(
              self.svg.slice(
                  serie_node,
                  slice_,
                  big_radius,
                  small_radius,
                  angle,
                  start_angle,
                  center,
                  val,
                  i,
                  metadata,
              ),
              metadata,
          )
          start_angle += angle
  
      if dual:
          val = self._serie_format(serie, sum(serie.values))
          self.svg.slice(
              serie_node,
              self.svg.node(slices, class_="big_slice"),
              radius * 0.9,
              0,
              serie_angle,
              original_start_angle,
              center,
              val,
              i,
              metadata,
          )
      return serie_angle
  
file_path: pygal/pygal/graph/pie.py
imports: from math import pi
  from pygal.adapters import none_to_zero, positive
  from pygal.graph.graph import Graph
  from pygal.util import alter, decorate
label_desc: Use image node_id 1 for calling the Pie obj's underlying member method code with example usage: obj.slice(serie, start_angle, total) and returns: serie_angle